Finding the right brush from huge collection always takes a lot of time. I've been trying to find a brush browser that would let you browse and organize your brushes to tabs and gives you the option to customize brush icon. It would also be very useful to have recent brushes tab so that you don't have to switch between tabs either.

Ok, I've been playing with photoshop scripting for couple days now and where it's very easy to create filters with static user interfaces, it turned out that it's more difficult to create custom tools that have dynamic panels (because of the way adobe has decided to not let the developers tamper with integrated UI stuff, or it could be that I just missed something). I still think that it might be possible, but I decided to start by making a tool that remembers your 20 recently used brushes and then expand the tool when I figure out how to do that exactly.

Interesting problem I face that quite often! and being quite ocd at times I had a go at it. lol

1. Separate out your categories and save them as a separate brush file
2. Make an action to load the corresponding file
3. Set actions to be displayed as "buttons" its on the drop-down list in the actions panel

click the button and it updates the brush to the category instantly, nice and orderly

I can find out if you could actually find all brush file from a folder and create corresponding number of buttons to a panel, find thumbnails for them and connect those buttons to certain actions.
Right now I'm still trying to find out how to create that recent brushes custom panel.
Biggest limitation I have found so far is that different photoshop versions are not compatible with each other, and seems like they made big changes to cs6 too from the User Interface side..

It looks that a lot of stuff is possible using flex I know there are windows applications that let you read and manage the .abr brush files so perhaps something like that which just exports files to the right places?

Someone has made a tool called Brusher. What the script does is allowes you to create custom thumbnails for brushes in your library. I don\t know how he managed to wiggle around those photoshop limitations, but it works perfectly.